Biological applications of quantum dots

1. A method of detecting biological moieties comprising:

providing a plurality of compositions capable of characteristic spectral emissions, the composition comprising a compound and a semiconductor nanocrystal associated with the compound, wherein each of the members of the plurality is characterized in that:

the nanocrystal of the member of the plurality has an emission spectrum distinct from the other members of the plurality and a quantum yield of greater than 10% in water, and

the compound of the member of the plurality has a corresponding biological moiety distinct from other biological moieties in the sample;

allowing a sample containing or suspected of containing one or more biological moieties to interact with the compositions; and

monitoring the spectral emission of each interaction between each composition and each biological moiety of the sample, wherein the interaction between the biological moiety and the composition comprises a noncovalent interaction.

2. The method of claim 1 , wherein the compound comprises a molecular complex with a molecule associated with the nanocrystal complexed to a second molecule that interacts with the biological moiety.

3. The method of claim 1 , wherein each interaction between each composition and each biological moiety of the sample are monitored substantially simultaneously.

4. The method of claim 1 , wherein the spectral emission provides information about a biological state or event.

5. The method of claim 4 , wherein the spectral emission provides information about the amount of biological moiety in the sample.

6. The method of claim 4 , wherein the spectral emission provides information about the presence of the biological moiety in the sample.

7. The method of claim 1 , wherein the semiconductor nanocrystal is water-soluble.

8. The method of claim 1 , wherein the semiconductor nanocrystal comprises a core comprising a semiconductor material, and a layer overcoating the core comprising a semiconductor material.

9. The method of claim 1 , wherein the spectral emission is tunable to a desired wavelength by controlling the size of the nanocrystal.

10. The method of claim 1 , wherein monitoring the spectral emission occurs in assays selected from the group consisting of:

immunochemistry, immunocytochemistry, immunobiology, immunofluorescence, DNA sequence analysis, fluorescence resonance energy transfer, flow cytometry, fluorescence activated cell sorting, diagnostics in biological systems, and high-throughput screening.

11. The method of claim 1 , wherein the noncovalent interaction comprises hydrophobic interaction, hydrophilic interaction, electrostatic interaction, van der Waals interaction, or magnetic interaction.

12. The method of claim 1 , wherein the biological moiety comprises a small molecule.

13. The method of claim 1 , wherein the biological moiety comprises a protein, peptide or antibody.

14. The method of claim 1 , wherein the biological moiety comprises a nucleic acid.

15. The method of claim 14 , wherein the nucleic acid comprises DNA or RNA.

16. The method of claim 1 , wherein the biological moiety comprises an amino acid.

17. The method of claim 1 , wherein the biological moiety comprises a ligand.

18. The method of claim 1 , wherein the biological moiety comprises an antigen.

19. The method of claim 1 , wherein the biological moiety comprises a cell.

20. The method of claim 1 , wherein the biological moiety comprises a subcellular organelle.

21. A method of detecting biological moieties comprising:

providing a plurality of compositions capable of characteristic spectral emissions, the composition comprising a compound and a semiconductor nanocrystal associated with the compound, wherein each of the members of the plurality is characterized in that:

the nanocrystal of the member of the plurality has an emission spectrum distinct from the other members of the plurality, and

the compound of the member of the plurality has a corresponding biological moiety distinct from other biological moieties in the sample and is associated with the nanocrystal by a ligand having at least one linking group for attachment to the nanocrystal spaced apart from a hydrophilic group by an alkyl or alkenyl group;

allowing a sample containing or suspected of containing one or more biological moieties to interact with the compositions; and

monitoring the spectral emission of each interaction between each composition and each biological moiety of the sample, wherein the interaction between the biological moiety and the composition comprises a noncovalent interaction.

22. The method of claim 21 , wherein the hydrophilic group is selected from the group consisting of carboxylic acid, carboxylate, sulfonate, hydroxide, alkoxide, ammonium, phosphate, and phosphonate.

23. The method of claim 21 , wherein each interaction between each composition and each biological moiety of the sample are monitored substantially simultaneously.

24. The method of claim 21 , wherein the spectral emission provides information about a biological state or event.

25. The method of claim 21 , wherein the semiconductor nanocrystal is water-soluble.

26. The method of claim 21 , wherein the semiconductor nanocrystal comprises a core comprising a semiconductor material, and a layer overcoating the core comprising a semiconductor material.

27. The method of claim 21 , wherein the biological moiety comprises a small molecule.

28. The method of claim 21 , wherein the biological moiety comprises a protein, peptide or antibody.

29. The method of claim 21 , wherein the biological moiety comprises a nucleic avid.

30. The method of claim 29 , wherein the nucleic acid comprises DNA or RNA.

31. The method of claim 21 , wherein the biological moiety comprises an amino acid.

32. The method of claim 21 , wherein the biological moiety comprises a ligand.

33. The method of claim 21 , wherein the biological moiety comprises an antigen.

34. The method of claim 21 , wherein the biological moiety comprises a cell.

35. The method of claim 21 , wherein the biological moiety comprises a subcellular organelle.

36. The method of claim 21 , wherein the spectral emission is tunable to a desired wavelength by controlling the size of the nanocrystal.

37. The method of claim 21 , wherein monitoring the spectral emission occurs in assays selected from the group consisting of:

immunochemistry, immunocytochemistry, immunobiology, immunofluorescence, DNA sequence analysis, fluorescence resonance energy transfer, flow cytometry, fluorescence activated cell sorting, diagnostics in biological systems, and high throughput screening.

38. The method of claim 21 , wherein the spectral emission is tunable to a desired wavelength by controlling the size of the nanocrystal.

39. The method of claim 21 , wherein monitoring the spectral emission occurs in assays selected from the group consisting of:

immunochemistry, immunocytochemistry, immunobiology, immunofluorescence, DNA sequence analysis, fluorescence resonance energy transfer, flow cytometry, fluorescence activated cell sorting, diagnostics in biological systems, and high throughput screening.

40. The method of claim 21 , wherein the noncovalent interaction comprises hydrophobic interaction, hydrophilic interaction, electrostatic interaction, van der Waals interaction, or magnetic interaction.